Allison

DIAGNOSTIC RESPONSE:
Use default values.

CIRCUIT DESCRIPTION:
SAE J1708 defines the hardware and general structure of this interface, while SAE J1587 defines the format of data and messages used. This two-wire twisted pair datalink offers low speed communication (9600 baud) intended for basic information sharing and diagnostics, such as:

1. Engine information received by the Transmission Control Module (TCM) for shift modulation and clutch control, and
2. Transmission information sent to driver displays or instrument clusters.

Due to its slow baud rate, SAE J1587 is not intended for vehicle control purposes. A41 and A51 model TCMs do not have SAE J1708/J1587 support. The 9-pin diagnostic tool connector has SAE J1708 SCI High (+) signal available on terminal F, and SAE J1708 SCI Low (-) signal available on terminal G. Terminal 32 of the TCMs is for SAE J1708 SCI High (+). Terminal 72 is SAE J1708 SCI Low (-). W132 and W172 are a twisted pair.

CONDITIONS FOR RUNNING THE DTC:
After TCM initializes normally.

CONDITIONS FOR SETTING THE DTC:
DTC U0100 sets when the TCM detects needed messages, such as throttle % and engine torque, that have not been received via the SAE J1708/J1587 SCI for 2 seconds or more.

NOTE: MY09 and later calibrations that did not maintain autodetect, i.e. did not roll forward from earlier software, should not be reprogrammed by the CMC Override Throttle Source. This disables some datalink features for the calibration’s specified communication link type. If a different throttle source is needed, calibrate with a new CIN that enables the desired throttle source.

ACTION TAKEN WHEN THE DTC SETS:
1. The TCM does not illuminate the CHECK TRANS light.
2. DTC is stored in TCM history.
3. Default throttle percentage is used for shift scheduling.
4. The TCM freezes shift adapts (DNA).

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
DTC U0100 indicates that a SAE J1708/J1587 communication interruption has occurred. This code may be caused by:
1. Miswired of defective OEM controllers, OEM components, or OEM circuits attached to SAE J1708. These may include:
– Electrical noise.
– Bus-loading.
2. Defective TCM.

The diagnostic tool does not communicate over SAE J1708. Use Data Bus viewer from the file menu to determine if data is streaming over the SAE J1708/J1587 SCI.

Review applicable information in the OEM Technician’s Library, Control System and Transmission Specifications, and other related information.

DIAGNOSTIC RESPONSE:
Maintain range selected, observe gear shift direction circuit

CIRCUIT DESCRIPTION:
The OEM 4th Generation Controls shift selectors communicate with the Transmission Control Module (TCM) by exchanging standardized digital messages over the SAE J1939 Controller Area Network (CAN). The physical network consists of a two-wire twisted-pair harness and, typically a third shield wire. A single 120 Ω termination resistor is located at each end of the network and produces 60 Ω resistance for the circuit. Vehicle OEMs may choose to install external termination resistors or use internal termination resistors built into many SAE J1939 electronic modules, including the TCM and shift selector. This DTC test verifies that there is SAE J1939 communication between the TCM and the primary SAE J1939 shift selector by monitoring a State of Health (SOH) message. This DTC is active when the SOH message is lost. Refer to the OEM Technician’s Library for additional information.

CONDITIONS FOR RUNNING THE DTC:
After TCM initializes normally and engine speed is above 200 rpm for more than 5 seconds.

CONDITIONS FOR SETTING THE DTC:
DTC U0103 sets when:
1. The TCM has not received a SAE J1939 SOH message from the active primary shift selector for 4 seconds.
2. The TCM has not received a SAE J1939 SOH message from an inactive primary shift selector for 8 seconds (for dual shift selector applications).
3. The shift selector is not strip shift selector.

NOTE: The primary shift selector is also referred to as Gear Shift Module 1 (Shift Selector).

ACTION TAKEN WHEN THE DTC SETS:
When DTC U0103 is active, the following conditions occur:
1. The DTC is stored in the TCM history.
2. The TCM illuminates the CHECK TRANS light.
3. The TCM upshifts and downshifts according to the PWM signal (W134) from shift selector.
4. If the shift selector has lost communications with the TCM, the TCM commands the last valid selected gear, and any pre-select capability is disabled.
5. When this DTC is active, the shift selector freezes the current display for about 1.5 seconds followed by 10.5 seconds of a blank display. If the shift selector still has power, then dual cat-eye symbols appear in both displays to notify the operator that range monitor and range select data is unavailable to the shift selector.

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
1. DTC U0103 indicates a missing datalink message for the shift selector SOH message. This DTC may be caused by:
– Miswired or mis-pinned shift selector harness.
– Loss ignition or battery power to primary shift selector.
– Miswired or defective OEM controllers, OEM components, or OEM circuits attached to the
datalink.
– Electrical noise.
– Bus-loading.
– Short to power or short to another wire in datalink wiring.
– High resistance or open in datalink wiring.
– Poor vehicle grounds.
– Unlocked connectors, expanded terminals, poor pin crimps or unlocked pins causing high
resistance or open circuit.
– Unlocked connectors, unlocked pins, causing shorts in connectors.
– TCM ground is at different voltage potential than the ground of the OEM voltage source
responsible for shift selector.
– Defective TCM.
– Defective shift selector.

2. Vehicle manufacturers may use the following terminal pairs for CAN 1 high and low wires:
– Terminals 8 and 28.
– Terminals 48 and 68.
– Both terminals 8 and 28 and terminals 48 and 68 are wired in a pass-through setup.

3. Vehicle manufacturers may wire the TCM into the CAN1 backbone in three different ways:
– The TCM may be on its own stub as in traditional CAN backbones.
– The TCM may be wired in a pass-through configuration so that the CAN high and low wires are
connected to two separate pin pairs in the TCM 80-way connector. Datalink messages pass-
through but can still be viewed by the TCM.
– The TCM may represent one end of the backbone. Typically, the internal resistor in the TCM will
be used in this setup.

4. An active DTC U0103 may prevent the diagnostic tool from communicating with the TCM. The J-47276 TCM Reflash Harness may be used to confirm that the TCM is operational. Connect the TCM Reflash Harness to the TCM and leave the OEM harness disconnected. Provide input power from the J-42455-A Load Box.

5. CAN1 and CAN2 devices must not be interconnected because they are incompatible with each other. CAN1 operates at 250 kbps data rate and CAN2 operates at 500 kbps data rate.

6. For proper datalink communications, it is necessary to have two 120 Ω resistors installed in parallel across the CAN1 High and CAN1 Low terminals. Resistance across CAN1 High and CAN1 Low should measure 60 Ω when wired correctly.

Review applicable information in the OEM Technician’s Library, Control System and Transmission Specifications, and other related information.

DIAGNOSTIC RESPONSE:
Use default values

CIRCUIT DESCRIPTION:
In OEM 4th Generation Controls, the preferred digital datalink is the SAE J1939 Controller Area Network (CAN). The Transmission Control Module (TCM) communicates with the engine control module and other controllers by exchanging standardized digital messages over SAE J1939. The physical network consists of a two-wire twisted pair, two 120 Ω termination resistors and, in most cases, a third shield wire. A 120 Ω termination resistor is located at each end of the network. Vehicle OEMs may choose to install external termination resistors or use internal termination resistors built into many SAE J1939 electronic modules, including the TCM and shift selector. Refer to the OEM Technician’s Library for additional information.

CONDITIONS FOR RUNNING THE DTC:
After TCM initializes normally and engine speed is above 200 rpm for more than 5 seconds, this DTC test will run at 0.1 second intervals.

CONDITIONS FOR SETTING THE DTC:
DTC U0115 sets when SAE J1939 engine torque, engine throttle. or engine coolant messages are not received for 5 seconds or more.

ACTION TAKEN WHEN THE DTC SETS:
1. The TCM does not illuminate the CHECK TRANS light.
2. DTC is stored in TCM history.
3. Default values are substituted for missing data, e.g., engine throttle percentage, engine torque, engine coolant temperature.
4. The TCM freezes shift adapts (DNA).

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
DTC U0115 indicates missing data on CAN1, i.e., either engine throttle, engine torque, or engine coolant temperature. This DTC may be caused by:
1. Engine DTCs. Some manufacturers may delay throttle, torque, or engine coolant temperature messages during their fault pending logic process, which may result in an active DTC U0115 on the transmission side.
2. Miswired or defective OEM controllers, OEM components, or OEM circuits attached to CAN 1. These may include:
– electrical noise.
– bus-loading.
3. Defective TCM.

Vehicle manufacturers may use the following terminal pairs for CAN 1 high and low wires:
1. Terminals 8 and 28.
2. Terminals 48 and 68.
3. Both terminals 8 and 28 and terminals 48 and 68 are wired in a pass-through setup.

Vehicle manufacturers may wire the TCM into the CAN1 backbone in three different ways:
1. The TCM may be on its own stub as in traditional CAN backbones.
2. The TCM may be wired in a pass-through configuration such that the CAN high and low wires are connected to two separate pin pairs in the TCM 80-way connector. Datalink messages pass-through but can still be viewed by the TCM.
3. The TCM may represent one end of the backbone. Typically, the internal resistor in the TCM will be used in this setup.

An active DTC U0115 may prevent the diagnostic tool from communicating with the TCM. The J-47276 TCM Reflash Harness may be used to confirm that the TCM is operational. Connect the TCM Reflash Harness to the TCM and leave the OEM harness disconnected. Provide input power from the J-42455-A Load Box.

CAN1 and CAN2 devices must not be interconnected because they are not compatible with each other. CAN1 operates at 250 kbps data rate and CAN2 operates at 500 kbps data rate.

For proper datalink communications, it is necessary to have two 120 Ω resistors installed in parallel across the CAN1 High and CAN1 Low terminals. Resistance across CAN1 High and CAN1 Low should measure 60 Ω when wired correctly.

Review applicable information in the OEM Technician’s Library, Control System and Transmission Specifications, and other related information.

DIAGNOSTIC RESPONSE:
Maintain range selected, observe gear shift direction circuit

CIRCUIT DESCRIPTION:
The OEM 4th Generation Controls shift selectors communicate with the Transmission Control Module (TCM) by exchanging standardized digital messages over the SAE J1939 Controller Area Network (CAN). The physical network consists of a two-wire twisted-pair harness and, typically, a third shield wire. A single 120 Ω termination resistor is located at each end of the network and produces 60 Ω resistance for the circuit. Vehicle OEMs may choose to install external termination resistors or use internal termination resistors built into many SAE J1939 electronic modules, including the TCM and shift selector. This DTC test verifies that there is SAE J1939 communication between the TCM and the secondary SAE J1939 shift selector by monitoring a State of Health (SOH) message. This DTC is active when the SOH message is lost. Refer to the OEM Technician’s Library for additional information.

CONDITIONS FOR RUNNING THE DTC:
After TCM initializes normally and engine speed is above 200 rpm for more than 5 seconds.

CONDITIONS FOR SETTING THE DTC:
DTC U0291 sets when:
1. The TCM has not received a SAE J1939 SOH message from the active secondary shift selector for 4 seconds.
2. The TCM has not received a SAE J1939 SOH message from an inactive secondary shift selector for 8 seconds (for dual shift selector applications).
3. The shift selector is not strip shift selector.

NOTE: The secondary shift selector is also referred to as Gear Shift Module 2 (Shift Selector).

ACTION TAKEN WHEN THE DTC SETS:
When DTC U0291 is active, the following conditions occur:
1. The DTC is stored in the TCM history.
2. The TCM illuminates the CHECK TRANS light.
3. The TCM upshifts and downshifts according to the PWM signal (W134) from shift selector.
4. If the shift selector has lost communications with the TCM, the TCM commands the last valid selected gear, and any pre-select capability is disabled.
5. When this DTC is active, this shift selector freezes the current display for about 1.5 seconds followed by 10.5 seconds of a blank display. If the shift selector still has power, then dual cat-eye symbols appear in both displays to notify the operator that range monitor and range select data is unavailable to the shift selector.

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
Use the OEM to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
1. DTC U0291 indicates a missing datalink message for the shift selector SOH message. This DTC may be caused by:
– Miswired or mis-pinned shift selector harness.
– Loss of ignition or battery power to secondary shift selector.
– Miswired or defective OEM controllers, OEM components, or OEM circuits attached to the
datalink.
– Electrical noise.
– Bus-loading.
– Short to power or short to another wire in datalink wiring.
– High resistance or open in datalink wiring.
– Poor vehicle grounds.
– Unlocked connectors, expanded terminals, poor pin crimps or unlocked pin causing high
resistance or open circuit.
– Unlocked connectors, unlocked pins, causing shorts in connectors.
– TCM ground is at different voltage potential than the ground of the OEM voltage source
responsible for shift selector.
– Defective TCM.
– Defective shift selector.
2. Vehicle manufacturers may use the following terminal pairs for CAN1 high and low wires:
– Terminals 8 and 28.
– Terminals 48 and 68.
– Both terminals 8 and 28 and terminals 48 and 68 are wired in a pass-through setup.
3. Vehicle manufacturers may wire the TCM into the CAN1 backbone in three different ways:
– The TCM may be on its own stub as in traditional CAN backbones.
– The TCM may be wired in a pass-through configuration so that the CAN high and low wires are
connected to two separate pin pairs in the TCM 80-way connector. Datalink messages pass-
through but can still be viewed by the TCM.
– The TCM may represent one end of the backbone. Typically, the internal resistor in the TCM will
be used in this setup.
4. An active DTC U0291 may prevent the diagnostic tool from communicating with the TCM. The J-47276 TCM Reflash Harness may be used to confirm that the TCM is operational. Connect the TCM Reflash Harness to the TCM and leave the OEM harness disconnected. Provide input power from the J-42455-A Load Box.
5. CAN1 and CAN2 devices must not be interconnected because they are incompatible with each other. CAN1 operates at 250 kbps data rate and CAN2 operates at 500 kbps data rate.
6. For proper datalink communications, it is necessary to have two 120 Ω resistors installed in parallel across the CAN1 High and CAN1 Low terminals. Resistance across CAN1 High and CAN1 Low should measure 60 Ω when wired correctly.

Review applicable information in the OEM Technician’s Library, Control System and Transmission Specifications, and other related information.

DIAGNOSTIC RESPONSE:
Ignore shift selector inputs

CIRCUIT DESCRIPTION:
The OEM 4th Generation Control shift selectors communicate with the Transmission Control Module (TCM) by exchanging standardized digital messages over the SAE J1939 Controller Area Network (CAN). The physical network consists of two-wire twisted-pair harness and, typically, a third shield wire. A single 120 Ω termination resistor is located at each end of the network and produces 60 Ω resistance for the circuit. Vehicle OEMs may choose to install external termination resistors or use internal termination resistors built into many SAE J1939 electronic modules, including the TCM and shift selector. This DTC test verifies that the primary shift selector is an approved ATI shift selector by reading the selector ID from the selector after starting the engine. The ID is requested only one time per ignition cycle after engine rpm reaches 200 rpm or more. Alternately, this code will set if a non-prognostics selector is installed in an application that has prognostics enabled in the TCM calibration. Refer to the OEM Technician’s Library for additional information.

CONDITIONS FOR RUNNING THE DTC:
After TCM initializes normal and engine speed is above 200 rpm for more than 5 seconds.

CONDITIONS FOR SETTING THE DTC:
DTC U0304 sets when:
1. The TCM has not received a valid shift selector ID from the primary shift selector for 3 seconds after the TCM request for selector ID was made.
2. A non-prognostics selector is installed in an application that has prognostics enabled in the TCM calibration.

NOTE: Non-prognostics selectors are those that do not have the small wrench icon between the range select and range monitor displays.

NOTE: The primary shift selector is also referred to as Gear Shift Module 1 (Shift Selector).

ACTION TAKEN WHEN THE DTC SETS:
When DTC U0304 is active for invalid ID, the following conditions occur:
1. The DTC is stored in the TCM history.
2. The TCM illuminates the CHECK TRANS light.
3. The transmission locks in Neutral (N).

When DTC U0304 is active for a non-prognostics selector in a prognostics enabled application, the following conditions occur:
1. The DTC is stored in the TCM history.
2. The TCM illuminates the CHECK TRANS light.
3. No other actions are taken. Transmission functions and shifts normally.

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC From the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
DTC U0304 indicates a missing or invalid ID message from the shift selector or a non-prognostics selector is installed in a prognostics enabled application.

When this DTC is active, possible causes for invalid selector ID include:
1. Insufficient battery capacity usually caused by excessive cranking, poor battery cabling, defective batteries, etc. Battery voltage dips below 7 to 8 volts occurring just after an initialized TCM makes the ID request is a common cause for this DTC. Generally this can happen during engine cranking above 200 rpm. The selector powers down but the TCM does not. The TCM will make one ID request per engine start cycle; if that request is missed by the selector (due to loss or low battery capacity) this DTC sets. Use the min-max feature on a digital voltmeter to capture the minimum voltage during cranking to the selector and to the TCM. Inspect battery capacity or battery charging issues if low battery voltages are intermittently occurring. Check that TCM and selector are referenced to the same ground points. Poor grounds or different ground levels to the TCM relative to the shift selector may cause this DTC.
2. Miswired or mis-pinned shift selector harness.
3. Loss of ignition or battery power to primary shift selector.
4. Miswired or defective OEM controllers, OEM components, or OEM circuits attached to the datalink.
5. Electrical noise.
6. Bus-loading.
7. Short to power or short to another wire in datalink wiring.
8. High resistance or open in datalink wiring.
9. Poor vehicle grounds.
10. Unlocked connectors, expanded terminals, poor pin crimps or unlocked pins causing high resistance or open circuit.
11. Unlocked connectors, unlocked pins, causing shorts in connectors.
12. TCM ground is at different voltage potential than the ground of the OEM voltage source responsible for shift selector.
13. Defective TCM.
14. Defective shift selector.

Vehicle manufacturers may use the following terminal pairs for CAN 1 high and low wires:
1. Terminals 8 and 28.
2. Terminals 48 and 68.
3. Both terminals 8 and 28 and terminals 48 and 68 are wired in a pass-through setup.

Vehicle manufacturers may wire the TCM into the CAN1 backbone in three different ways:
1. The TCM may be on its own stub as in traditional CAN backbones.
2. The TCM may be wired in a pass-through configuration so that the CAN high and low wires are connected to two separate pin pairs in the TCM 80-way connector. Datalink messages pass-through but can still be viewed by the TCM.
3. The TCM may represent one end of the backbone. Typically, the internal resistor in the TCM will be used in this setup.

CAN1 and CAN2 devices must not be interconnected because they are incompatible with each other. CAN1 operates at 250 kbps data rate and CAN2 operates at 500 kbps data rate.

For proper datalink communications, it is necessary to have two 120 Ω resistors installed in parallel across the CAN1 High and CAN1 Low terminals. Resistance across CAN1 High and CAN1 Low should measure 60 Ω when wired correctly.

When this DTC is active for a non-prognostics shift selector installed with a prognostics enabled TCM calibration, either replace the selector with an approved prognostics capable shift selector or disable prognostics using the diagnostic tool.

Review applicable information in the OEM Technician’s Library, Control System and Transmission Specifications, and other related information.

DIAGNOSTIC RESPONSE:
Ignore shift selector inputs

CIRCUIT DESCRIPTION:
The OEM 4th Generation Control shift selectors communicate with the Transmission Control Module (TCM) by exchanging standardized digital messages over the SAE J1939 Controller Area Network (CAN). The physical network consists of a two-wire twisted-pair harness and, typically, a third shield wire. A single 120 Ω termination resistor is located at each end of the network and produces 60 Ω resistance for the circuit. Vehicle OEMs may choose to install external termination resistors or use internal termination resistors built into many SAE J1939 electronic modules, including the TCM and shift selector. This DTC test verifies that the secondary shift selector is an approved ATI shift selector by reading the selector ID from the selector after starting the engine. The ID is requested only one time per ignition cycle after engine rpm reaches 200 rpm or more. Alternately, this code will set if a non-prognostics selector is installed in an application that has prognostics enabled in the TCM calibration. Refer to the OEM Technician’s Library for additional information.

CONDITIONS FOR RUNNING THE DTC:
After TCM initializes normally and engine speed is above 200 rpm for more than 5 seconds.

CONDITIONS FOR SETTING THE DTC:
DTC U0333 sets when:
1. The TCM has not received a valid shift selector ID from the secondary shift selector for 3 seconds after the TCM request for selector ID was made.
2. A non-prognostics selector is installed in an application that has prognostics enabled in the TCM calibration.

NOTE: Non- prognostics selectors are those that do not have the small wrench icon between the range select and range monitor displays.

NOTE: The secondary shift selector is also referred to as Gear Shift Module 2 (Shift Selector).

ACTION TAKEN WHEN THE DTC SETS:
When DTC U0333 is active for invalid ID, the following conditions occur:
1. The DTC is stored in the TCM history.
2. The TCM illuminates the CHECK TRANS light.
3. The transmission locks in Neutral (N).

When DTC U0333 is active for a non-prognostics selector in a prognostics enabled application, the following conditions occur:
1. The DTC is stored in the TCM history.
2. The TCM illuminates the CHECK TRANS light.
3. No other actions are taken. Transmission functions and shifts normally.

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without DTC recurring.

DIAGNOSTIC AIDS:
DTC U0333 indicates a missing or invalid ID message from the shift selector or a non-prognostics selector is installed in a prognostics enabled application.

When this DTC is active, possible causes for invalid selector ID include:
1. Insufficient battery capacity usually caused by excessive cranking, poor battery cabling, defective batteries, etc. A battery voltage dip below 7 to 8 volts occurring just after an initialized TCM makes the ID request a common cause for this DTC. Generally this can happen during engine cranking above 200 rpm. The selector powers down but the TCM does not. The TCM will make one ID request per engine start cycle; if that request is missed by the selector (due to loss or low battery capacity) this DTC sets. Use the min-max feature on a digital voltmeter to capture the minimum voltage during cranking to the selector and to the TCM. Inspect battery capacity or battery charging issues if low battery voltages are intermittently occurring. Check that TCM and selector are referenced to the same ground points. Poor grounds or different ground levels to the TCM relative to the shift selector may cause this DTC.
2. Miswired or mis-pinned shift selector harness.
3. Loss of ignition or battery power to secondary shift selector.
4. Miswired or defective OEM controllers, OEM components, or OEM circuits attached to the datalink.
5. Electrical noise.
6. Bus-loading.
7. Short to power or short to another wire in datalink wiring.
8. High resistance or open in datalink wiring.
9. Poor vehicle grounds.
10. Unlocked connectors, expanded terminals, poor pin crimps or unlocked pins causing high resistance or open circuit.
11. Unlocked connectors, unlocked pins, causing shorts in connectors.
12. TCM ground is at different voltage potential than the ground of the OEM voltage source responsible for shift selector.
13. Defective TCM.
14. Defective shift selector.

Vehicle manufacturers may use the following terminal pairs for CAN 1 high and low wires:
1. Terminals 8 and 28.
2. Terminals 48 and 68.
3. Both terminals 8 and 28 and terminals 48 and 68 are wired in a pass-through setup.

Vehicle manufacturers may wire the TCM into the CAN1 backbone in three different ways:
1. The TCM may be on its own stub as in traditional CAN backbones.
2. The TCM may be wired in a pass-through configuration so that the CAN high and low wires are connected to two separate pin pairs in the TCM 80-way connector. Datalink messages pass-through but can still be viewed by the TCM.
3. The TCM may represent one end of the backbone. Typically, the internal resistor in the TCM will be used in this setup.

CAN1 and CAN2 devices must not be interconnected because they are incompatible with each other. CAN1 operates at 250 kbps data rate and CAN2 operates at 500 kbps data rate.

For proper datalink communications, it is necessary to have two 120 Ω resistors installed in parallel across the CAN1 High and CAN1 Low terminals. Resistance across CAN1 High and CAN1 Low should measure 60 Ω when wired correctly.

When this DTC is active for a non-prognostics shifts selector installed with a prognostics enabled TCM calibration, either replace the selector with an approved prognostics capable shift selector for disable prognostics using the diagnostic tool.

Review applicable information in the OEM Technician’s Library, Control System and Transmission Specifications, and other related information.

DIAGNOSTIC RESPONSE:
None

CIRCUIT DESCRIPTION:
In 4th Generation Controls, the preferred digital datalink is the SAE J1939 Controller Area Network (CAN). The Transmission Control Module (TCM) communicates with the engine control module and other controllers by exchanging standardized digital messages over SAE J1939. The physical network consists of a two-wire twisted pair, two 120 Ω termination resistors and, in most cases, a third shield wire. A 120 Ω termination resistor is located at each end of the network. Vehicle OEMs may choose to install external termination resistors or use internal termination resistors built into many SAE J1939 electronic modules, including the TCM and shift selector. Refer to the OEM Technician’s Library for additional information.

CONDITIONS FOR RUNNING THE DTC:
1. TCM initializes normally and engine speed is above 200 rpm for more than 5 seconds.
2. TCM calibrated to receive SAE J1939 Brake Signal message, also known as Service Brake Switch (SBS) Status from proper OEM controller and Source Address (SA).

CONDITIONS FOR SETTING THE DTC:
SAE J1939 SBS message indicates “Error”, “Not Available” or missing for a time.

ACTION TAKEN WHEN THE DTC SETS:
1. The TCM illuminates the CHECK TRANS light.
2. MY09 and later illuminates the service indicator in the shift selector.
3. DTC is stored in TCM history.
4. Various features and/or ranges may be inhibited when a valid SBS state is not detected by the TCM. The range inhibit light will illuminate when range is inhibited.

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
NOTE: DTC U0400 indicates SAE J1939 SBS message indicates “Error”, “Not Available” or missing for a time.

This DTC may be caused by:
1. Malfunctioning brake system control components such as:
– Miswired or defective brake system wiring.
– Defective, loose, or vibration at brake system wheel speed sensors.
– Defective brake pressure switches.
2. OEM controller hardware or software issue with body, engine, or brake system controller (e.g., ABS/ATC/ASR, etc.)
3. OEM SAE J1939 datalink integrity issues such as:
– Wiring shorted to ground.
– Wiring open circuit or high resistance.
– Shielding problems.
– Termination resistors missing, defective, or unplugged.
– Electrical noise issues.
– Bus loading issues.
4. Defective TCM.

When reviewing Data Bus Viewer logs, determine which Source Address (SA) brake switch status message is being received by the TCM. SAE J1939 EBC1 and CCVS Brake Switch messages may be received from several source addresses. The TCM locks on the most preferred, even if the message sent by that controller is ‘error’. EBC1 Brake switch messages have preference over CCVS during the SA autodetect process. Reset Autodetect to reset the SA autodetect process.

SBS message status must be monitored using the Data Bus Viewer. The “Brake Pedal Depressed” status is displayed when the service brake is applied. The “Brake Pedal Released” is displayed when the brake is not applied. Verify EBC1 Brake Switch status is shown as “Not Available” before assuming brake switch is being received by the TCM from a CCVS SA.

If the TCM calibration is configured to receive both an analog (hardwire input) vehicle service brake signal (e.g., W162) as well as an SAE J1939 SA SBS message, then the TCM will consider the brake as depressed either when the wire input is in an active ON state or the autodetected brake pedal status message of “Brake Pedal Depressed” is being sent and received. Refer to OEM Datalink Tech Data, the OEM Technician’s Library when troubleshooting brake status related complaints (such as issues with 1/0, retarder apply, or DTCs) to determine if either the wired input or the controller message for SBS can be disabled to correct the complaint.

When a controller broadcasts an SAE J 1939-based brake switch parameter, which has been autodetected as the SBS source by the TCM, it is considered an SBS input for the transmission controls and 1/0 even if the vehicle OEM intended for SBS is available to the TCM as an analog only input. Datalink tailoring may be required for some applications to prevent this interaction.

Some controllers might erroneously broadcast a continuous SAE J1939 Brake Switch status message of “Brake Pedal Depressed” if the OEM does not hardwire the brake switch input to that controller. If the OEM brake switch circuit has an issue or the programmable CMC for the controller is not set correctly (e.g., for the brake switch input on the engine TCM) then the SBS will be considered in a stuck active state after several acceleration/deceleration cycles, and the TCM sets DTC P0703.

Not all input functions incorporating Service Brake Status may substitute a SAE J 1939-based input for the analog input. The functions that do not allow an SBS datalink message (see info below) must use an analog input for SBS. Refer to the OEM Technician’s Library for additional information. Features and/or ranges may be inhibited when a valid SBS state is not detected by the TCM.

OEM Input Function:
1. E Auxiliary Function Range Inhibit – Single Input (AFRI)
– SBS Datalink Message Allowed

2. AA Service Brake Status
– SBS Datalink Message Allowed

3. CA Brake Based Auto-Neutral For PTO (BBAN)
– SBS Datalink Message Allowed

4. W Direction Change Enable
– SBS Datalink Message Allowed

5. Z Retarder Enable (see Driveline Retarder Control)
– SBS Datalink Message Allowed

6. AK Automatic Neutral – Dual Input with Service Brake Status
– SBS Datalink Message Allowed

7. AL Shift Selector Transition/Secondary Shift Schedule
– SBS Datalink Message NOT Allowed

8. AS Reduced Engine Load at Stop (RELS)
– SBS Datalink Message NOT Allowed

9. BB RELS with Service Brake Status
– SBS Datalink Message NOT Allowed

Vehicle manufacturers may wire the TCM into the CAN 1 backbone in three different ways:
1. The TCM may be on its own stub as in traditional CAN backbones.
2. The TCM may be wired in a pass-through configuration such that the CAN high and low wires are connected to two separate pin pairs in the TCM 80-way connector. Datalink messages pass through but can still be viewed by the TCM.
3. The TCM may represent one end of the backbone. Typically, the internal resistor in the TCM will be used in this setup.

CAN1 and CAN2 devices must not be interconnected because they are incompatible. CAN1 operates at 250 kbps data rate and CAN2 operates at 500 kbps data rate.

For proper datalink communications, it is necessary to have two 120 Ω resistors installed in parallel across the CAN1 High and CAN1 Low terminals. Resistance across CAN1 High and CAN1 Low should measure 60 Ω when wired correctly.

Review applicable information in the OEM Technician’s Library, Control System and Transmission Specifications, and other related information.

DIAGNOSTIC RESPONSE:
Maintain range selected, observe gear shift direction circuit

CIRCUIT DESCRIPTION:
The OEM 4th Generation Controls shift selectors communicate with the Transmission Control Module (TCM) by exchanging standardized digital messages over the SAE J1939 Controller Area Network (CAN). The physical network consists of two-wire twisted-pair harness and, typically, a third shield wire. A single 120 Ω termination resistor is located at each end of the network and produces 60 Ω resistance for the circuit. Vehicle OEMs may choose to install external termination resistors or use internal termination resistors built into many SAE J1939 electronic modules, including the TCM and shift selector. This DTC test verifies that the primary shift selector messages are valid from the selector after starting the engine. Refer to the OEM Technician’s Library for additional information.

CONDITIONS FOR RUNNING THE DTC:
After TCM initializes normally and engine speed is above 200 rpm for more than 5 seconds.

CONDITIONS FOR SETTING THE DTC:
DTC U0404 sets when:
1. The TCM has not received valid shift selector data from primary shift selector for 4 seconds.
2. The TCM has not received valid shift selector data from an inactive primary shift selector for 8 seconds.

NOTE: The primary shift selector is also referred to as Gear Shift Module 1 (Shift Selector).

ACTION TAKEN WHEN THE DTC SETS:
When DTC U0404 is active when the following conditions occur:
1. The DTC is stored in the TCM history.
2. The TCM illuminates the CHECK TRANS light.
3. While shift selector data is invalid, the TCM maintains last valid selected gear, and pre-select capability is disabled. The Pulse Width Modulation (PWM) circuit is used to select direction.

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
DTC U0404 indicates invalid data is received from the primary shift selector and may be caused by:
1. Insufficient battery capacity usually caused by excessive cranking, poor battery cabling, defective batteries, etc. A battery voltage dip below 7 to 8 volts while the TCM continues to check for valid shift selector messages is a common cause for this DTC. Generally this can happen during engine cranking above 200 rpm. The selector powers down but the TCM does not. Use the min-max feature on a digital voltmeter to capture the minimum voltage during cranking to the selector and to TCM. Inspect battery capacity or battery charging issues if low battery voltages are intermittently occurring. Check that TCM and selector are referenced to the same ground points. Poor grounds or different ground levels to the TCM relative to the shift selector may cause this DTC.
2. Miswired or mis-pinned shift selector harness.
3. Loss of ignition or battery power to primary shift selector.
4. Miswired or defective OEM controllers, OEM components, or OEM circuits attached to the datalink.
5. Electrical noise.
6. Bus-loading.
7. Short to power or short to another wire in datalink wiring.
8. High resistance or open in datalink wiring.
9. Poor vehicle grounds.
10. Unlocked connectors, expanded terminals, poor pin crimps or unlocked pins causing high resistance or open circuit.
11. Unlocked connectors or unlocked pins causing shorts in connectors.
12. TCM ground is at different voltage potential than the ground of the OEM voltage source responsible for shift selector.
13. Defective TCM.
14. Defective shift selector.
15. Vehicle manufacturers may use the following terminal pairs for CAN1 high and low wires:
– Terminals 8 and 28.
– Terminals 48 and 68.
– Both terminals 8 and 28 and terminals 48 and 68 are wired in pass-through setup.
16. Vehicle manufacturers may wire the TCM into the CAN1 backbone in three different ways:
– The TCM may be on its own stub as in traditional CAN backbones.
– The TCM may be wired in a pass-through configuration so that the CAN high and low wires
are connected to two separate pin pairs in the TCM 80-way connector. Datalink messages pass-
through but can still be viewed by the TCM.
– The TCM may represent one end of the backbone. Typically, the internal resistor in the TCM will
be used in this setup.
17. CAN1 and CAN2 devices must not be interconnected because they are incompatible with each other. CAN1 operates at 250 kbps data rate and CAN2 operates at 500 kbps data rate.
18. For proper datalink communications, it is necessary to have two 120 Ω resistors installed in parallel across the CAN1 High and CAN1 Low terminals. Resistance across CAN1 High and CAN1 Low should measure 60 Ω when wired correctly.

Review applicable information in the OEM Technician’s Library, Control System and Transmission Specifications, and other related information.

DIAGNOSTIC RESPONSE:
None

CIRCUIT DESCRIPTION:
In OEM 4th Generation Controls, the preferred digital datalink is the SAE J1939 Controller Area Network (CAN). The Transmission Control Module (TCM) communicates with the engine control module and other controllers by exchanging standardized digital messages over SAE J1939. The physical network consists of a two-wire twisted pair, two 120 Ω termination resistors and, in most cases, a third shield wire. A 120 Ω termination resistor is located at each end of the network. Vehicle OEMs may choose to install external termination resistors or use internal termination resistors built into many SAE J1939 electronic modules, including the TCM and shift selector. Refer to the OEM Technician’s Library for additional information.

CONDITIONS FOR RUNNING THE DTC:
1. After TCM initializes normally and engine speed is above 200 rpm for more than 5 seconds, this DTC test will run at 0.1 second intervals.
2. SAE J1939 EC1 engine controller message is available.

CONDITIONS FOR SETTING THE DTC:
DTC U0442 sets when the TCM detects engine derate in the Engine Configuration (EC) message sent by the engine controller. The TCM defines engine derate when the EC message contains current maximum engine torque or power data that is less than the TCMs learned maximum engine torque or power.

ACTION TAKEN WHEN THE DTC SETS:
1. The TCM does not illuminate the CHECK TRANS light.
2. DTC is stored in the TCM history.
3. TCM substitutes percent load for accelerator pedal position and adjusts shift schedule.

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DTC U0442 is self-clearing when engine derate is not active.

DIAGNOSTIC AIDS:
DTC U0442 indicates engine is derating. This DTC may be caused by:
– Engine DTCs.
– Low engine power.